十二进制计数器

郑州科技学院

《数字电子技术》课程设计

题 目 十二进制计数器 学生姓名 丁洪宝 专业班级 电科一班 学 号 201031018 院 （系） 电气工程学院 指导教师 袁玉霞 完成时间 2013年03月15日

目 录

1 实验概述 ······························································································ 1 1.1 计数器设计目的 ········································································ 2 1.2 计数器设计组成 ········································································ 2 2 十二进制计数器设计描述 ··························································· 2 2.1 设计原理 ······················································································ 2 2.2 设计的思路 ················································································· 3 2.3 设计的实现 ·················································································· 4 3 十二进制计数器的设计与仿真 ················································· 5 3.1 基本电路分析设计 ··································································· 5 3.2 计数器电路的仿真 ·································································· 8 4 总结 ········································································································ 9 参考文献 ································································································· 11 附录1：实验电路图 ·········································································· 12 附录2：元器件清单 ·········································································· 13

1 实验简述

计数器是一个用以实现计数功能的时序部件，它不仅可用来及脉冲数，还常用作数子系统的定时、分频和执行数字运算以及其它特定的逻辑功能。

计数器种类很多。按构成计数器中的各触发器是否使用一个时钟脉冲源来分，有同步计数器和异步计数器。根据计数制的不同，分为二进制计数器、十进制计数器和任意进制计数器。根据计数器的增减趋势，又分为加法、减法和可逆计数器。还有可预制数和可变程序功能计数器等等。目前，无论是TTL还是CMOS集成电路，都有品种较齐全的中规模集成计数器。使用者只要借助于器件手册提供的功能和工作波形图以及引出端的排列，就能正确运用这些器件。

计数器在现代社会中用途中十分广泛，在工业生产、各种和记数有关电子产品。如定时器，报警器、时钟电路中都有广泛用途。在配合各种显示器件的情况下实现实时监控，扩展更多功能。

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1.1 计数器设计目的

1) 每隔1s，计数器增1；能以数字形式显示时间。 2) 熟练掌握计数器的各个部分的结构。 3) 计数器间的级联。

4) 不同芯片也可实现十二进制。

1.2 计数器设计组成

1) 用两个74LS160芯片和一个与非门实现。

2) 当定时器递增到12时，定时器会自动返回到01显示，然后继续计时。

本设计主要设备是两个74LS160同步十进制计数器，并且由200HZ，5V电源供给。作高位芯片与作低芯片位之间级联。

2 十二进制计数器设计描述

2.1 设计原理

74LS160是十进制计数器，要实现十二进制计数器必

须用两片实现级联，把各位芯片预置1，当数码管显示9时，个位芯片开始进位即B端为0C端为1，经过与非门输出高电平，十位芯片开始工作，十位芯片由0变为

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